Oil well drilling structure



y 21,1964 0. JENKINS OIL WELL DRILLING STRUCTURE Filed March 11, 1963 wwjvron car/1. JENKINS.

8mm, 5 Mam.

ATTORNEYS.

United States Patent 3,141,653 OIL WELL DLING STRUCTURE Cecil Jenkins, Tulsa, Okla, assignor to Lee C. Moore Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed Mar. 11, 1963, Ser. No. 264,091 2 Claims. (Cl. 254-439) This invention relates to oil well drilling structures, and more particularly to the way in which hinged drilling masts are raised and lowered.

It is now common practice to erect an oil well drilling mast by first assembling it in reclining position along the ground with the foot of the mast pivotally mounted in shoes on a substructure or base. A gin pole is erected on the base behind the recliining mast. A line extends from drawworks, also mounted on the base, up over the top of the gin pole and forward to the crown block at the front end of the reclining mast. From there the line extends back into the mast to support a travelling block. The central part of a cable sling is looped over the book of the travelling block, and the two sides of the sling extend back beneath sheaves journaled in the mast and then up to the top of the gin pole. If the mast is short, the ends of the sling line are anchored to the gin pole, but if the mast is tall it is advantageous to extend the sling line around sheaves supported by the top of the gin pole and then forward to the top of the reclining mast, to which the ends of the sling line are anchored. When the drawworks is operated to pull the travelling block toward the crown block of the mast, the sling is pulled farther into the mast, with the result that the mast is swung to upright position against he gin pole.

The cross sectional size, and therefore the strength, of

' the sling line is limited by the physical difficulty of handling large size lines. On the other hand, the erection of the mast is a secondary function of the travelling block, the capacity and available distance for travel of which is determined by its primary function, which is to pull pipe out of the well. The length of travel of the block obviously is limited by the height of the mast. Hence, it is necessary to consider the height of the gin pole, the size of the sling line and the manner of reeving of the sling in relation to the fixed limitations of the travelling block. The manner of reeving the sling line referred to in the preceding paragraph for relatively tall masts has the advantage of reducing the sling load. However, such reeving is not satisfactory with some masts that have been built more recently, which are considerably heavier than those erected heretofore. A new arrangement therefore was called for.

It is among the objects of this invention to provide an oil Well drilling structure, in which a hinged mast of great height and weight can be swung up to upright position by the travelling block without imposing too great a sling line load and without requiring the travelling block to travel farther than theretofore.

In accordance with this invention two slings are used. They extend around the front of a pair of parallel upper and lower travelling sheaves carried by the travelling block and then extend back under two laterally spaced pairs of substantially vertical sheaves mounted in the upper part of the reclining mast. One end of one sling is connected to the top of the gin pole near one side of it, and the other end of that sling extends back under a gin pole sheave at the opposite side and up around it and forward to connection with the top of the reclining mast in front of the mast sheaves. One end of the other sling is connected to the top of the gin pole adjacent the gin pole sheave, and the other end of that sling extends back under another gin pole sheave at the opposite side and up around it and forward to connection with the top of the mast in front of the mast sheaves. When the drawworks is operated to pull the travelling sheaves away from the gin pole, the slings help swing the mast upward and backward toward the gin pole to upright position.

The preferred embodiment of the invention is illustrated in the accompanying drawings, in which FIG. 1 is a side view of a reclining mast about to be raised; and

FIG. 2 is an enlarged somewhat diagrammatic perspective view of the sling arrangement for raising the mast.

Referring to FIG. 1- of the drawings, a mast substructure 1 of any suitable construction is erected at the well location. Mounted in front and rear shoes 2 and 3 on the substructure are the upwardly converging legs of a gin pole 4. Pivotally mounted at 6 in the front shoes is the foot of a reclining mast 7 that extends forward away from the base. The outer or front end of the mast supports the usual crown block 8, through which pass lines 9 that extend back through the mast to a travelling block 10. A continuation 11 of these lines extends from the crown block back above the mast and down around a sheave 12 (FIG. 2), journaled at the center ofthe top of the gin pole, to drawworks 13 mounted on the substructure. It will be seen that when the drawworks is operated to wind up the line, the travelling block will be pulled forward toward the crown block.

To aid in erecting the mast, two sling lines 14 and 15 are provided, as best shown in FIG. 2. The central portions of these two lines are looped around a pair of parallel upper and lower travelling sheaves 16 and 17 forming part of an equalizer removably attached to the travelling block. The equalizer includes a heavy plate 18 provided with a slot 19 for the hook 20 of the travelling block, and also with a hole for a substantially vertical pin 21, on the opposite ends of which the two sheaves are rotatably mounted.

Behind the equalizer two laterally spaced pairs 23 and 24 of sugstantially vertical sheaves are mounted in the upper part of the reclining mast. The sling lines extend from the equalizer back under all four of these mast sheaves, a different part of the slings engaging each sheave. From one of the mast sheaves 23 one end of sling line 14 extends back to the top of the gin pole where it is anchored at 25 in any suitable manner. The opposite end of this sling line extends from the other pair of mast sheaves 24 back under and then up and around a sheave 26 journaled at the top of the gin pole at the side opposite anchor point 25. From this sheave the line extends forward and is anchored in any suitable manner to the top of the reclining mast at 27 some distance ahead of the mast sheaves. Likewise, one end of the other sling line 15 extends from a mast sheave 24 back to the top of the gin pole and is fastened to it at 28. The opposite end of this sling extends back around a sheave 29 journaled in the top of the gin pole near the anchor point of the first sling and then extends forward to the top of the reclining mast, where it is secured at 30 beside the other sling, but at the opposite side of the mast.

When the drawworks is operated to pull the travelling block toward the crown block, the equalizer pulls the slings in the same direction farther into the mast, so the slings help swing the mast upward and back against the gin pole to the dotted upright position. Although the general way in which the slings raise the mast is similar to What has been done heretofore, by the use of two sling lines and the particular way in which they are reeved, a new and unexpected result occurs. The load on the hook is taken by what amounts to six lines instead of the usual two or four, so a greater load can be handled, or the same load with lighter sling lines. Furthermore, a mechanical advantage is obtained, which is much greater 3 than that obtained heretofore. By this system which makes good use of available block travel, lower erection loads are provided than otherwise would be the case.

When it is desired to lower the mast, it is pulled forward over dead center by a suitable auxiliary line (not shown) and then the slings aid in supporting the tilting mast and controlling its descent to the ground.

I claim:

1. In an oil well drilling structure, the combination with a base, drawworks mounted thereon, a gin pole mounted on said base, a reclining mast hinged to the base in front of the gin pole and extending forward away from it, a line extending from the drawworks up over the gin pole and forward to the front end of the mast and then back inside the mast, and a pair of laterally spaced substantially vertical sheaves mounted on top of the gin pole; of a pair of parallel upper and lower travelling sheaves carried by said line inside the mast, two laterally spaced pairs of substantially vertical sheaves mounted in the upper part of the reclining mast behind said travelling sheaves, and two sling lines extending around the front of the travelling sheaves and back under said mast sheaves, one end of one sling being connected to the top of the gin pole near one side thereof and the other end of that sling extending back under the gin pole sheave at the opposite side and up around it and forward to connection with the top of the reclining mast in front of the mast sheaves, and one end of the other sling being connected to the top of the gin pole near said opposite side and the other end of that sling extending back under the other gin pole sheave and up around it and forward to connection with said mast top in front of the mast sheaves, whereby when said drawworks is operated to pull the travelling sheaves away from the gin pole the slings will help swing the mast upward and backward toward the gin pole to upright position.

2. In an oil well drilling structure, the combination with a base, drawworks mounted thereon, a gin pole mounted on said base, a mast hinged to the base in front of the gin pole for swinging forward and downward into prone position along the ground, a line extending from the drawworks upward behind the top of the gin pole to the top of the mast and then downward inside of it, and a pair of laterally spaced substantially vertical sheaves mounted on top of the gin pole; of a pair of parallel travelling sheaves carried by said line inside the mast above the gin pole on an axis extending from front to back of the mast, two laterally spaced pairs of substantially vertical sheaves mounted in the back part of the mast in front of said gin pole sheaves, and two sling lines suspended from said travelling sheaves and extending down and back under said mast sheaves, one end of one sling being connected to the top of the gin pole near one side of it and the other end of that sling extending back under the gin pole sheave at the opposite side and upwardly therefrom to connection with the back of the mast above that sheave, and one end of the other sling being connected to the top of the gin pole near said opposite side and the other end of that sling extending back under the other gin pole sheave and upwardly therefrom to connection with the back of the mast above it, whereby when said drawworks is operated to lower the travelling sheaves inside the mast the slings will control the forward and downward swinging of the mast.

References Cited in the file of this patent UNITED STATES PATENTS 2,570,901 Woolslayer Oct. 9, 1951 

1. IN AN OIL WELL DRILLING STRUCTURE, THE COMBINATION WITH A BASE, DRAWWORKS MOUNTED THEREON, A GIN POLE MOUNTED ON SAID BASE, A RECLINING MAST HINGED TO THE BASE IN FRONT OF THE GIN POLE AND EXTENDING FORWARD AWAY FROM IT, A LINE EXTENDING FROM THE DRAWWORKS UP OVER THE GIN POLE AND FORWARD TO THE FRONT END OF THE MAST AND THEN BACK INSIDE THE MAST, AND A PAIR OF LATERALLY SPACED SUBSTANTIALLY VERTICAL SHEAVES MOUNTED ON TOP OF THE GIN POLE; OF A PAIR OF PARALLEL UPPER AND LOWER TRAVELLING SHEAVES CARRIED BY SAID LINE INSIDE THE MAST, TWO LATERALLY SPACED PAIRS OF SUBSTANTIALLY VERTICAL SHEAVES MOUNTED IN THE UPPER PART OF THE RECLINING MAST BEHIND SAID TRAVELLING SHEAVES, AND TWO SLING LINES EXTENDING AROUND THE FRONT OF THE TRAVELLING SHEAVES AND BACK UNDER SAID MAST SHEAVES, ONE END OF ONE SLING BEING CONNECTED TO THE TOP OF THE GIN POLE NEAR ONE SIDE THEREOF AND THE OTHER END OF THAT SLING EXTENDING BACK UNDER THE GIN POLE 